Re: FreeBSD 5.3b7and poor ata performance

From: Brad Knowles <brad_at_stop.mail-abuse.org>
Date: Mon, 25 Oct 2004 23:39:57 +0200
At 3:25 PM -0600 2004-10-25, Scott Long wrote:

>                                       But as was said, there is always
>  a performance vs. reliability tradeoff.

	Well, more like "Pick two: performance, reliability, price"  ;)

>                                           And when you are talking about
>  RAID-10 with a bunch of disks, you will indeed start seeing bottlenecks
>  in the bus.

	When you're talking about using a lot of disks, that's going to 
be true for any disk subsystem that you're trying to get a lot of 
performance out of.

	The old rule was that if you had more than four disks per 
channel, you were probably hitting saturation.  I don't know if that 
specific rule-of-thumb is still valid, but I'd be surprised if disk 
controller performance hasn't roughly kept up with disk performance 
over time.

-- 
Brad Knowles, <brad_at_stop.mail-abuse.org>

"Those who would give up essential Liberty, to purchase a little
temporary Safety, deserve neither Liberty nor Safety."

     -- Benjamin Franklin (1706-1790), reply of the Pennsylvania
     Assembly to the Governor, November 11, 1755

   SAGE member since 1995.  See <http://www.sage.org/> for more info.
Received on Mon Oct 25 2004 - 19:40:09 UTC

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